Methods, algorithms, and computer codes for calculation of electron-impact excitation parameters

Abstract

We describe the computer codes, developed at Vilnius University, for the calculation of electron-impact excitation cross sections, collision strengths, and excitation rates in the plane-wave Born approximation. These codes utilize the multireference atomic wavefunctions which are also adopted to calculate radiative transition parameters of complex many-electron ions. This leads to consistent data sets suitable in plasma modelling codes. Two versions of electron scattering codes are considered in the present work, both of them employing configuration interaction method for inclusion of correlation effects and Breit-Pauli approximation to account for relativistic effects. These versions difer only by one-electron radial orbitals, where the first one employs the nonrelativistic numerical radial orbitals, while the other version uses the quasirelativistic radial orbitals. The accuracy of produced results is assessed by comparing radiative transition and electron-impact excitation data for neutral hydrogen, helium, and lithium atoms as well as highly charged tungsten ions with theoretical and experimental data available from other sources.

Atomic Data for Zn Ii: Improving Spectral Diagnostics of Chemical Evolution in High-Redshift Galaxies

“…Following the methods of Bogdanovich et al (2014), we also produce electron-impact excitation collision strengths in the plane-wave Born approximation. The most inclusive description of the adopted approach is given by Bogdanovich (2004Bogdanovich ( , 2005, whereas its application for data production and their accuracy analysis is given by Bogdanovich & Martinson (1999); Bogdanovich et al (2003a,b); ; Kupliauskienė et al (2006).…”

“…Along with the radiative transition data, we have determined electron-impact excitation parameters for these lines in the plane-wave Born approximation. The methods and codes for such calculation are described by Bogdanovich et al (2014). We present just a sample of the collisional parameters in Table 4, whereas the complete version of the table is available on-line.…”

Energy level properties of 4p$^6$4d$^3$, 4p$^6$4d$^2$4f and 4p$^5$4d$^4$ configurations of W$^{35+}$ ion

“…We have investigated the transitions among the levels of different configurations and among the levels of same configurations. Furthermore, the electron-impact excitation cross-sections and collision strengths were calculated in the plane-wave-Born approximation with a new computer code described in [31] for all considered levels.…”

Energy spectra of the tungsten ion 4s24pN, 4s24N–14d and 4s4pN+1 configurations

“…Furthermore, the plane-waves Born approximation is used to calculate the electron-impact cross-sections and collision strengths for all investigated levels of the tungsten ions. The calculation method is described in [34]. In the current work we present only the energy levels and compare them with the experimental, semiempirical and theoretical data from other authors.…”